Bordetella pseudohinzii targets cilia and impairs tracheal cilia-driven transport in naturally acquired infection in mice

Several species of the Gram-negative genus Bordetella are the cause of respiratory infections in mammals and birds, including whooping cough (pertussis) in humans. Very recently, a novel atypical species, Bordetella pseudohinzii, was isolated from laboratory mice. These mice presented no obvious clinical symptoms but elevated numbers of neutrophils in bronchoalveolar lavage fluid and inflammatory signs in histopathology. We noted that this species can occur at high prevalence in a mouse facility despite regular pathogen testing according to the FELASA-recommendations. Affected C57BL/6 J mice had, in addition to the reported pulmonary alterations, tracheal inflammation with reduced numbers of ciliated cells, slower ciliary beat frequency, and largely (>50%) compromised cilia-driven particle transport speed on the mucosal surface, a primary innate defence mechanism. In an in vitro-model, Bordetella pseudohinzii attached to respiratory kinocilia, impaired ciliary function within 4 h and caused epithelial damage within 24 h. Regular testing for this ciliotropic Bordetella species and excluding it from colonies that provide mice for lung research shall be recommended. On the other hand, controlled colonization and infection with Bordetella pseudohinzii may serve as an experimental model to investigate mechanisms of mucociliary clearance and microbial strategies to escape from this primary innate defence response.

The presence of bacterial microcolonies on the maxillary sinus ciliary epithelium in healthy young individuals

OBJECTIVE

The aim of this cross-sectional in vitro study was to evaluate the mucosal surfaces of healthy maxillary sinuses, explore different forms of bacterial microorganism colonies present on the mucous membrane, and determine a mucosal surface area they occupy.

METHODS

Samples of the maxillary sinus mucosa were collected from 30 healthy patients (M = 11; F = 19). The material was obtained during the Le Fort I osteotomy performed during corrective jaw surgery. The morphological and morphometric analysis of sinus mucosa and bacterial film that was grown on it was performed using scanning electron microscopy (SEM) as well as imaging software.

RESULTS

Scanning electron microscopy analysis showed the presence of different bacterium and bacteria-like structures in all the analyzed samples. In most cases, the bacterial film was mostly composed of diplococci-like and streptococci-like structures on the mucosa of the paranasal sinus. In any case, the mucous layer did not cover the whole lining of the evaluated sample. Each colony consists of more than 20 single bacterial cells, which has grown in aggregates.

CONCLUSIONS

Under the conditions of normal homeostasis of the body, the maxillary sinuses present diverse bacterial colonization. The bacteria are dispersed or concentrated in single microcolonies of the biofilm on the border of the mucous covering the ciliary epithelium. There is no uniform layer of the biofilm covering the mucosa of the maxillary sinuses. Because the biofilm is detected on healthy individuals sinus mucosa, the clinical question if it may become pathogenic is unclear and require an explanation.

Human polymorphonuclear leukocytes inhibit Aspergillus fumigatus conidial growth by lactoferrin-mediated iron depletion

Aspergillus fumigatus, a common mold, rarely infects humans, except during prolonged neutropenia or in cases of chronic granulomatous disease (CGD), a primary immunodeficiency caused by mutations in the NADPH oxidase that normally produces fungicidal reactive oxygen species. Filamentous hyphae of Aspergillus are killed by normal, but not CGD polymorphonuclear leukocytes (PMN); however, the few studies on PMN-mediated host defenses against infectious conidia (spores) of this organism have yielded conflicting results, some showing that PMN do not inhibit conidial growth, with others showing that they do, most likely using reactive oxygen species. Given that CGD patients are exposed daily to hundreds of viable A. fumigatus conidia, yet considerable numbers of them survive years without infection, we reasoned that PMN use ROS-independent mechanisms to combat Aspergillus. We show that human PMN from both normal controls and CGD patients are equipotent at arresting the growth of Aspergillus conidia in vitro, indicating the presence of a reactive oxygen species-independent factor(s). Cell-free supernatants of degranulated normal and CGD neutrophils both suppressed fungal growth and were found to be rich in lactoferrin, an abundant PMN secondary granule protein. Purified iron-poor lactoferrin at concentrations occurring in PMN supernatants (and reported in human mucosal secretions in vivo) decreased fungal growth, whereas saturation of lactoferrin or PMN supernatants with iron, or testing in the presence of excess iron in the form of ferritin, completely abolished activity against conidia. These results demonstrate that PMN lactoferrin sequestration of iron is important for host defense against Aspergillus.

Bacterial biofilms in chronic rhinosinusitis

Chronic sinusitis is a prevalent, debilitating condition, and a subpopulation of patients fails to respond to either medical or surgical intervention. Bacterial biofilms are 3-dimensional aggregates of bacteria that have special properties due to their group structure, including increased resistance to antibiotics in some forms. They have been shown to play a major role in many chronic infections, including cystic fibrosis, endocarditis, and otitis media. Evidence now suggests that they may play an important role in chronic sinusitis. Our laboratory has identified the presence of biofilms in sinonasal mucosa isolated from human patients and on stents removed after frontal sinus surgery. In addition, biofilms have been found on the sinus epithelium of rabbits infected with Pseudomonas aeruginosa, but not in rabbits infected with non-biofilm-forming P. aeruginosa mutants. This animal model can provide opportunities to address the functional significance of biofilm production in the sinus cavities. A further understanding of the role of bacterial biofilms may lead to the development of more appropriate therapies for the treatment and prevention of chronic sinusitis.

A model of the deciliation process caused by Mycoplasma fermentans strain incognitus on respiratory epithelium

The aim of this study was to investigate by light microscopy as well as by scanning and transmission electron microscopy the deciliation process which takes place on the respiratory epithelium of tracheal explants after experimental infection with Mycoplasma fermentans strain incognitus. Time-point photography allowed distinguishing five phases which occurred during the infection on the epithelial cell surface: (1) Attachment of M. fermentans to the cilia causing clumping of the cilia tips; (2) matting of cilia into bundles; (3) formation of abnormally shaped and shorter cilia; (4) collapse of cilia onto the epithelial cell surface; and (5) widespread loss of cilia. Based on the photographic images, a schematic model of the deciliation process was developed. Various potential factors contributing to the cilia destruction are discussed, including the release of mycoplasmal toxins, the physical presence of a high number of M. fermentans cells attached to the cilia, and the depletion of culture medium components by the mycoplasmas. This model of M. fermentans strain incognitus infection of respiratory epithelium is important for understanding mycoplasmal pathogenicity on a comparative level.

Cilia-associated respiratory (CAR) bacillus infection in adult red deer, chamois, and roe deer

Cilia-associated respiratory (CAR) bacillus is an unclassified bacterium that colonizes the ciliated epithelium of airways in laboratory rats, laboratory mice, and laboratory and conventionally reared rabbits, cattle, goats, and pigs. Data on the prevalence of CAR bacillus infection in wild animals are lacking. The present study demonstrated the occurrence of the organism in wild red deer (Cervus elaphus hippelaphus), chamois (Rupicapra rupicapra), and roe deer (Capreolus capreolus) from the Val Fontana in northern Italy. Prevalence ranged from 26% for red deer to 56% for chamois, with a statistically significant negative correlation between CAR bacilli infection and the presence of lymphoid follicles.

Ultrastructural analysis of the pathogenesis of Neisseria gonorrhoeae endometrial infection

We have studied gonococcal infection in human endometrium organ culture and in human primary endometrial epithelial cells using various microscopic techniques including scanning electron microscopy, transmission electron microscopy, bright field light microscopy and laser scanning confocal microscopy. Here we describe the interactions between Neisseria gonorrhoeae and human endometrial luminal epithelial cells at the ultrastructural levels. N. gonorrhoeae attached to cilia but were not observed associated with the plasma membrane of ciliated epithelial cells or internalized into ciliated epithelial cells. N. gonorrhoeae could be found in intracellular vacuoles in secretory epithelial cells. N. gonorrhoeae have diverse interactions with endometrial epithelium. These include intimate association and colocalization with asialoglycoprotein receptor (ASGP-R) and CEACAM, lamellipodia and ruffle formation and colocalization with CR3, and microvillus engagement. These studies indicate that N. gonorrhoeae utilize multiple mechanisms to associate with endometrial epithelial cells and can associate with both ciliated and secretory cells. This diversity is consistent with a role of the endometrium as a transition zone between frequently asymptomatic cervical gonorrhoea and symptomatic pelvic inflammatory disease.

Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces

Cystic fibrosis (CF) lung disease is characterized by persistent lung infection. Thickened (concentrated) mucus in the CF lung impairs airway mucus clearance, which initiates bacterial infection. However, airways have other mechanisms to prevent bacterial infection, including neutrophil-mediated killing. Therefore, we examined whether neutrophil motility and bacterial capture and killing functions are impaired in thickened mucus. Mucus of three concentrations, representative of the range of normal (1.5 and 2.5% dry weight) and CF-like thickened (6.5%) mucus, was obtained from well-differentiated human bronchial epithelial cultures and prepared for three-dimensional studies of neutrophil migration. Neutrophil chemotaxis in the direction of gravity was optimal in 1.5% mucus, whereas 2.5% mucus best supported neutrophil chemotaxis against gravity. Lateral chemokinetic movement was fastest on airway epithelial surfaces covered with 1.5% mucus. In contrast, neutrophils exhibited little motility in any direction in thickened (6.5%) mucus. In in vivo models of airway mucus plugs, neutrophil migration was inhibited by thickened mucus (CF model) but not by normal concentrations of mucus ("normal" model). Paralleling the decreased neutrophil motility in thickened mucus, bacterial capture and killing capacity were decreased in CF-like thickened mucus. Similar results with each mucus concentration were obtained with mucus from CF cultures, indicating that inhibition of neutrophil functions was mucus concentration dependent not CF source dependent. We conclude that concentrated ("thick") mucus inhibits neutrophil migration and killing and is a key component in the failure of defense against chronic airways infection in CF.

Bordetella bronchiseptica adherence to cilia is mediated by multiple adhesin factors and blocked by surfactant protein A

In the virulent state (Bvg+), Bordetella bronchiseptica expresses adhesins and toxins that mediate adherence to the upper airway epithelium, an essential early step in pathogenesis. In this study, we used a rabbit tracheal epithelial cell binding assay to test how specific host or pathogen factors contribute to ciliary binding. The host antimicrobial agent surfactant protein A (SP-A) effectively reduced ciliary binding by Bvg+ B. bronchiseptica. To evaluate the relative contributions of bacterial adhesins and toxins to ciliary binding, we used mutant strains of B. bronchiseptica in the binding assay. When compared to Bvg+ or Bvg- phase-locked B. bronchiseptica strains, single-knockout strains lacking one of the known adhesins (filamentous hemagglutinin, pertactin, or fimbriae) displayed an intermediate ciliary binding capacity throughout the coincubation. A B. bronchiseptica strain deficient in adenylate cyclase-hemolysin toxin also displayed an intermediate level of adherence between Bvg+ and Bvg- strains and had the lowest ciliary affinity of any of the Bvg+ phase strains tested. A B. bronchiseptica strain that was missing dermonecrotic toxin also displayed intermediate binding; however, this strain displayed ciliary binding significantly higher than most of the adhesin knockouts tested. Taken together, these findings suggest that virulent-state B. bronchiseptica expresses multiple adhesins with overlapping contributions to ciliary adhesion and that host production of SP-A can provide innate immunity by blocking bacterial adherence to the ciliated epithelium.

Bacterial biofilms in surgical specimens of patients with chronic rhinosinusitis

OBJECTIVES

Biofilms are bacterial pathogens that organize in several chronic and recalcitrant infectious processes. We hypothesize that biofilms play a role in chronic rhinosinusitis (CRS). Our goal is to demonstrate biofilms in mucosal specimens of patients undergoing surgery for CRS.

STUDY DESIGN

A prospective study of the presence of biofilms in patients undergoing endoscopic sinus surgery for CRS compared with control patients without CRS.

METHODS

There were a total of 30 subjects and 4 controls enrolled. The samples of 24 subjects and 4 controls were cultured and then prepared using standard methods for scanning electron microscopy (SEM). The remaining six subjects' samples were treated using advanced cryofixation methods as preparation to preserve structure for SEM and transmission electron microscopy (TEM).

RESULTS

Using strict SEM morphologic criteria, 24 (80%) of the 30 patients were found to have micrographic evidence of biofilms. All controls had healthy appearing cilia and goblet cells without biofilms. The six cryofixation samples showed biofilm structures on SEM micrographs that were correlated with bacterial structures seen at the mucosal surface on the corresponding TEM cross sections. Bacterial cultures were positive on all patients.

CONCLUSIONS

Biofilms were demonstrated to be present in patients undergoing surgery for CRS; none of the patients without CRS had any evidence of biofilms. Although SEM is capable of demonstrating the biofilms' three-dimensional structure, glycocalyx, and water channels, it cannot clearly demonstrate the presence of bacteria within the biofilm. We were able to demonstrate evidence of bacteria in the biofilms on the subjects tested using TEM.

Ciliostasis is a key early event during colonization of canine tracheal tissue by Bordetella bronchiseptica

The primary site of infection for Bordetella bronchiseptica, Bordetella pertussis and Bordetella parapertussis is the ciliated respiratory epithelium. Previous studies have implicated adherence of bacteria to cilia, induction of mucus production, induction of ciliostasis and damage to the ciliated epithelium in Bordetella pathogenesis. This paper describes the use of an air-interface organ culture system using canine tracheal tissue infected with B. bronchiseptica to assess the temporal relationship between these pathologies. Ciliostasis occurs very early during the host tissue-pathogen interaction, before mucus production and obvious signs of epithelial damage occur. A B. bronchiseptica bvg mutant does not colonize the organ culture model, induce ciliostasis or cause damage to the epithelial cell layer, but it does induce similar amounts of mucus release as does infection by wild-type bacteria. The authors propose that ciliostasis is a key early event during the B. bronchiseptica-host tissue interaction that abrogates the muco-ciliary defences of the host tissue, renders it susceptible to colonization by the bacteria and allows subsequent damage to the epithelium. The organ culture model described offers a physiologically relevant tool with which to characterize the molecular basis for interactions between Bordetella and its primary site of infection, the ciliated respiratory epithelium.

Proteolytic processing of the Mycoplasma hyopneumoniae cilium adhesin

Mycoplasma hyopneumoniae is an economically significant swine pathogen that colonizes the respiratory ciliated epithelial cells. Cilium adherence is mediated by P97, a surface protein containing a repeating element (R1) that is responsible for binding. Here, we show that the cilium adhesin is proteolytically processed on the surface. Proteomic analysis of strain J proteins identified cleavage products of 22, 28, 66, and 94 kDa. N-terminal sequencing showed that the 66- and 94-kDa proteins possessed identical N termini and that the 66-kDa variant was generated by cleavage of the 28-kDa product from the C terminus. The 22-kDa product represented the N-terminal 195 amino acids of the cilium adhesin preprotein, confirming that the hydrophobic leader signal sequence is not cleaved during translocation across the membrane. Comparative studies of M. hyopneumoniae strain 232 showed that the major cleavage products of the cilium adhesin are similar, although P22 and P28 appear to be processed further in strain 232. Immunoblotting studies using antisera raised against peptide sequences within P22 and P66/P94 indicate that processing is complex, with cleavage occurring at different frequencies within multiple sites, and is strain specific. Immunogold electron microscopy showed that fragments containing the cilium-binding site remained associated with the cell surface whereas cleavage products not containing the R1 element were located elsewhere. Not all secreted proteins undergo multiple cleavage, however, as evidenced by the analysis of the P102 gene product. The ability of M. hyopneumoniae to selectively cleave its secreted proteins provides this pathogen with a remarkable capacity to alter its surface architecture.

Scanning electron microscopic studies of Mycoplasma gallisepticum infection in embryonic tracheae

Mycoplasma gallisepticum (MG) was used to infect chicken embryos, and scanning electron microscopy was used to examine the morphologic changes in the tracheae. Tracheae harvested from embryos infected with MG for 5 days showed extensive deciliation, surface erosion, and inflammatory cell infiltration. Embryonic tracheal explants infected with MG for 6 hr showed the same deciliation and surface erosion. The damage to the tracheal surface caused by MG at the embryonic stage might play a role in the pathogenesis of MG infection.

Indoor fungi and their ciliostatic metabolites

According to epidemiological studies, it is possible that some secondary metabolites of indoor airborne fungi could be responsible for health troubles which occupants suffer from. In our previous experiments, a model with tracheal rings of 1-day-old chicks in vitro was shown to be a very suitable method to study the ciliostatic chloroform-extractable endo- and/or exometabolites of filamentous fungi. In this study we isolated the filamentous fungi from walls of "mouldy" dwellings and schools (cultivation on dichloran 18% glycerol agar at 25 and 37 degrees C for 10 d) in Slovakia. We studied the ciliostatic effect of the chloroform-extractable endo- and exometabolites of 96 representative isolates (stationary cultivation on the liquid medium with 2% of yeast extract and 10% of sucrose at 25 degrees C for 10 days) on the cilia movement in tracheal organ cultures of 1-day-old chickens in vitro after 24, 48 and 72 hrs (incubation in the minimal essential medium according to Eagle with Earl s salts and 20 microg of extract of metabolites dissolved in dimethylsulfoxide per 1 mL). Strains of Penicillium Link: Fr. sp., Aspergillus versicolor (Vuill.) Tiraboschi, A. flavus Link, Cladosporium sphaerospermum Penzig and C. cladosporioides (Fres.) de Vries were isolated most frequently. Two A. flavus isolates were able to produce aflatoxins B1, B2, G1, G2 in vitro after cultivation on the liquid medium with 20% sucrose and 2% yeast extract. This is the first isolation of aflatoxigenic A. flavus strains from dwellings in Slovakia. All frequently isolated strains produced secondary metabolites with the strongest ciliostatic activity -- their exo- and endometabolites stopped tracheal ciliary movement in chicks till 24 h. There are some toxic fungal metabolites in the indoor air not only with the ability to destroy ciliary movement in the upper airways in vitro but, probably, during long-lasting exposure to cause general intoxication of macroorganism via lung tissue.

Cilia-Associated Respiratory (CAR) bacillus infection in veal calves and adult cattle

Cilia-Associated Respiratory (CAR) bacillus is a filamentous bacterium that colonizes the ciliated epithelium of the respiratory tract of many animal species and that has been associated with chronic inflammatory lesions in naturally and experimentally infected rats, mice and rabbits. In the present study, the prevalence of CAR bacillus infection and histological lesions of the trachea in veal calf and adult cattle were investigated. Forty five healthy veal calves and 45 adult cattle, raised in 18 different herds were selected at slaughter. From each animal, a tracheal sample was processed for histology, stain-ed with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was identified in 17 veal calves (37.7%) and in 7 adult cattle (15.5%). Inflammatory lesions were found in 42 veal calves (93.3%) and in 41 adult cattle (91.1%). Statistical analysis pointed out a significant correlation between the presence and number of CAR bacilli and the presence and number of lymphoid follicles (P = 0.0071) and the presence and severity of neutrophilic infiltrates (P = 0.0428). These results indicate that CAR bacillus infection is common in cattle and is correlated with tracheal inflammatory lesions.

Secondary ciliary dyskinesia in upper respiratory tract

The system of mucociliary clearance has the important task to remove from the airways inhaled substances and locally formed secretions. Inborn disorders of the mucociliary transport are due to ciliary dysfunction (Primary Ciliary Dyskinesia) (PCD) or of increased viscosity of the bronchial secretions (Cystic Fibrosis). To differentiate PCD from the ultrastructural abnormalities found during or after injuries such as respiratory infections, the name of Secondary--or acquired--Ciliary Dyskinesia (SCD) was created. In controls, less than 4% of the cilia may show ultrastructural abnormalities. The most frequent of these are the compound cilia and the peripheral microtubular abnormalities. Compound cilia often appear after infection and therefore are thought to arise secondarily. Secondary ultrastructural abnormalities of cilia include also blebs of the axoneme membrane, ciliary disorientation, and absence of axoneme membrane. No increase in ultrastructural ciliary abnormalities has been found in a variety of respiratory disorders: smoking, asthma and allergic rhinitis, chronic rhinitis and sinusitis, chronic bronchitis, cystic fibrosis, and lung carcinoma. But severe modifications of the respiratory epithelium can be seen. Important for the secondary ciliary disorders is their local and reversible character. To distinct from ultrastructural images between primary and secondary ciliary dyskinesia is often uneasy because some of the findings in secondary ciliary dyskinesia obviously mimic those dedicated to primary ciliary dyskinesia.

Ectosymbiotic bacteria on ciliated cells of a rotifer

During the examination of Brachionus plicatilis (Rotifera, Monogononta), ectosymbiotic bacteria were found in the ciliated buccal region. These have about the same dimensions as the cilia and possess a specific apical region that apparently serves to attach the bacterium to its host cell. This apical region resembles a vesicle but is interpreted as a specialized region of the bacterial nucleocytoplasm devoid of ribosomes and chromatin strands but containing a crystalline rod. The bacterium has two membranes (as have other Gram-negative bacteria) also over the apical region. Thin strands join the two membranes and similar strands extend from the bacterium to the cell membrane of the host cell. No intracellular bacteria were found in this study.

The pathogenesis of nontypable Haemophilus influenzae otitis media

Nontypable Haemophilus influenzae is a common cause of otitis media and initiates infection by colonizing the upper respiratory tract. In this article, I review our current understanding of the molecular determinants of H. influenzae colonization and discuss the relationship between colonization and otitis media.

Sequence of 16S rRNA gene of rat-origin cilia-associated respiratory (CAR) bacillus SMR strain

The 16S rRNA gene of the SMR strain of cilia-associated respiratory (CAR) bacillus, which was isolated from a spontaneously infected rat at our institute, was sequenced. Its 1,521 nucleotides were determined. On the basis of the results of the sequence analysis, the SMR strain was found to be most closely related to members of the Flavobacter/Flexibacter group. This sequence was compared with the previously determined 16S rRNA gene sequences (rat-origin: three; mouse-origin: one; rabbit-origin: one) of CAR bacillus isolates. The SMR strain showed the highest sequence similarity (99.9%) to the rat-origin CARB-NIH strain (Schoeb et al., 1993), and it was concluded that the strains are identical.

A tissue culture system to study respiratory ciliary epithelial adherence of selected swine mycoplasmas

An in vitro culture system for swine tracheal epithelial cells was developed to study the adherence of swine mycoplasmas. Swine tracheal epithelial cells were isolated by enzymatic digestion and cultured on microporous membranes. Growth medium was placed under the membrane support to create air-liquid interface feeding resulting in the cells growing cilia and microvilli on the apical surface. Two strains of Mycoplasma hyopneumoniae (pathogenic strain 91-3 and non-pathogenic type strain J) and two strains of Mycoplasma flocculare (type strain Ms42 and field isolate 7160T) were used in this study. The morphology of the cultured tracheal cells was evaluated by transmission electron microscopy. Adherence of M. hyopneumoniae and M. flocculare and damage to the cilia were demonstrated using scanning electron microscopy. The pathogenic M. hyopneumoniae strain 91-3 adhered to cilia inducing obvious damage. The non-pathogenic M. hyopneumoniae strain J did not adhere to mature cilia. Both M. flocculare strains Ms42 and 7160T adhered to mature and budding cilia. No obvious ciliary damage was observed with strain Ms42. Minimal damage consisting of a slight tangling of the cilia occurred after adherence by strain 7160T. This model will enable us to further study the role of adherence of mycoplasmas on the pathogenesis of swine pneumonia.

Isolation of cilia-associated respiratory (CAR) bacillus from pigs and calves and experimental infection of gnotobiotic pigs and rodents

Filamentous, gram-negative bacteria morphologically similar to cilia-associated respiratory (CAR) bacillus of rodents and rabbits were isolated from the tracheas of 5 pigs and 4 calves. All pigs but none of the calves had histologic lesions of chronic tracheitis. In silver-stained histologic sections, CAR bacilli were adhered to the tracheal epithelium of each pig but were not found in the calves. Like CAR bacillus of rats, the bacteria displayed gliding motility and grew only in cell culture or cell culture medium supplemented with fetal serum. Initially, all isolates were contaminated by Mycoplasma spp. This contamination was eliminated from 4 pig isolates by limiting dilutions, and mycoplasma-free isolates were used to intranasally inoculate gnotobiotic pigs and CAR bacillus-free mice and rats and to immunize guinea pigs. The gnotobiotic pigs remained healthy, and when they were necropsied 4 and 7 weeks after infection no macroscopic or microscopic lesions were found in the respiratory tract. However, CAR bacillus was isolated at both times from the nasal cavities and tracheas of inoculated pigs, and the ciliated tracheal epithelium of infected pigs necropsied 7 weeks after infection was colonized by low numbers of CAR bacillus-like bacteria. The rats and mice remained healthy through week 12 postinoculation, and evidence of short- or long-term colonization was not detected by histologic examination or culture. When used as primary antibody for immunohistochemical staining, sera from guinea pigs immunized with pig CAR bacillus specifically stained CAR bacilli colonizing the respiratory epithelium of naturally infected pigs, whereas sera collected prior to immunization failed to react with the bacteria. These results indicate that CAR bacilli are unlikely to be primary pathogens of pigs or cattle and that rodents do not act as reservoirs.

Cilia-associated respiratory (CAR) bacillus infection in conventionally reared rabbits

This study was designed to investigate the prevalence of Cilia-associated respiratory (CAR) bacillus infection in rabbits reared for meat production in Italy and to correlate the presence of CAR bacillus with inflammatory lesions of the respiratory tract. Seventy health, 3-month-old, New Zealand White rabbits, raised in 10 different rabbitries in Northern Italy were randomly selected at slaughter. No gross lesions were found at necropsy in any rabbit. In each animal, the trachea and lungs were sampled, fixed in 10% formalin, embedded in paraffin and stained with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was present in 50 out of 70 rabbits (71.4%) with a prevalence of the infection that varied from 30% to 100% in the seven rabbitries. CAR bacillus was present both in the trachea and bronchi in 23 cases (32.8%), only in the trachea in 24 cases (34.3%) and only in the bronchi in three cases (4.3%). Inflammatory lesions were found in the trachea (22 cases, 31.4%) and the bronchi (58 cases, 82.8). There was a strong, statically significant correlation between the presence of CAR bacillus in the bronchi and bronchial inflammatory lesions (P < 0.0001). This study indicates that CAR bacillus infection is widespread in conventionally reared rabbits in Italy and that a possible correlation exists between the presence of CAR bacillus and bronchial inflammatory lesions.

Antigenic analyses of cilia-associated respiratory (CAR) bacillus isolates by use of monoclonal antibodies

Mouse monoclonal antibodies (MAbs) developed to a rat isolate (R-3) of cilia-associated respiratory (CAR) bacillus were used to assess antigenic relationships among three rat and five rabbit CAR bacillus isolates. Evaluation of MAbs by enzyme-linked immunosorbent assays (ELISAs) indicated that 87 of 241 hybridomas secreted CAR bacillus-reactive antibodies that could be grouped into four major groups. Group-I MAbs reacted with epitopes expressed by all CAR bacillus isolates and at least two or more nonrelated species of bacteria. Group-II, -III, and -IV MAbs reacted with only one or more of the rat CAR bacillus isolates; no MAbs reacted only with rat and rabbit CAR bacillus isolates. Western blot analyses indicated that 41-, 50-, and 105-kDa peptides of rat CAR bacillus isolates expressed rat CAR bacillus group- and isolate-specific epitopes. Hyperimmune anti-CAR bacillus antiserum and serum specimens from a CAR bacillus histologically positive mouse and rat also reacted with the 41-, 50-, and 105-kDa peptides. Sera from CAR bacillus histologically negative rats did not react with these peptides. These results suggest that the 41-, 50-, and 105-kDa peptides may represent suitable antigens for development of a specific ELISA for detection of rodent CAR bacillus infections. Furthermore, these data indicate that use of crude CAR bacillus preparations for either rat or rabbit CAR bacillus ELISAs is inappropriate.

Field isolates of Mycoplasma ovipneumoniae exhibit distinct cytopathic effects in ovine tracheal organ cultures

Ovine tracheal ring explants were infected with four different Mycoplasma ovipneumoniae and one M. arginini field isolate and their ability to induce cytopathic effects was tested by measuring ciliary activity and intracellular calmodulin release. Infected tracheal rings showed significantly decreased ciliary activity as compared to the non-infected control rings. There were, however, marked differences between isolates in the onset and severity of the effects which correlated with their ability to produce hydrogen peroxide. Infected tracheal rings released more calmodulin than the non-infected controls. The amount of calmodulin released also varied between isolates, and somewhat reflected the degree of loss of ciliary activity in the corresponding rings induced by the different isolates. Light and electron microscopic examinations of infected tracheal rings revealed disorganisation and sloughing of the epithelium, and association of mycoplasmas only with the cilia. Following repeated in vitro passages, the organisms had reduced ability to inhibit ciliary activity which correlated with decreased hydrogen peroxide production. Addition of catalase to the organ cultures delayed loss of ciliary activity. These results suggest that M. ovipneumoniae induced ciliostasis in ovine tracheal ring explants which correlated with hydrogen peroxide production. Furthermore, these M. ovipneumoniae-induced injuries to respiratory epithelial cells could contribute to the role that this organism may play in sheep respiratory disease.

Molds on house walls and the effect of their chloroform-extractable metabolites on the respiratory cilia movement of one-day-old chicks in vitro

The ciliostatic activity of the chloroform-extractable endo- and exometabolites of 5 strains of filamentous fungi--Alternaria sp., Aspergillus glaucus group, Aspergillus versicolor, Cladosporium sphoerospermum, Penicillium sp. and Ulocladium sp.--isolated from molded walls of a dwelling--on tracheal cilia from 1-d-old chicks in vitro was evaluated. Endometabolites of Alternaria sp. and A. versicolor and exometabolites of Ulocladium sp. were the most active, these extracts stopped the ciliary movement within 1 d. The results are discussed in relation to the health status of people living in "moldy" dwellings.

Association of cilia-associated respiratory (CAR) bacillus with natural chronic tracheitis in goats

A histological, histochemical and immunohistological study of the respiratory tract of 83 slaughtered goats (50 adults and 33 kids) is described. Cilia-associated respiratory (CAR) bacillus was detected by means of the Warthin Starry method in the tracheal epithelium of seven (21.2%) of the kids and 16 (32%) of the adult goats. A chronic diffuse tracheitis characterized by mixed lymphocyte and plasma-cell infiltration was found in all seven kids and in 17 adults, including the 16 infected with the CAR bacillus. Although not proved, it is possible that the CAR bacillus caused the chronic tracheitis. Immunohistochemical results suggested that the caprine CAR bacillus was closely related to the rabbit CAR bacillus.

Natural cilia-associated respiratory bacillus infection in rabbits used for elaboration of hyperimmune serum against Mycoplasma sp

Cilia-associated respiratory (CAR) bacillus was identified in lung lesions of rabbits used for elaboration of hyperimmune serum against Mycoplasma mycoides ssp. capri (Mmc). Numerous Warthin Starry (WS) positive filamentous bacteria aligned perpendicularly to the surface of bronchial epithelial lining were observed. Immunoperoxidase staining of these bacteria was detected using a serum anti-rabbit CAR bacillus. Ultrastructural morphology corresponds to that of CAR bacilli previously reported in rabbits. The desirability of monitoring laboratory rabbits for CAR bacillus infection as part of the health programme is reinforced, especially in rabbits used for raising sera against respiratory pathogens of animal species in which CAR bacillus infection has been described. This is the first report of natural CAR bacillus infection in rabbits in Europe.

Pathogenicity of cilia-associated respiratory (CAR) bacillus isolates for F344, LEW, and SD rats

We conducted experiments to test whether rats of F344, LEW, and SD strains differ in susceptibility to mycoplasma-free isolates of cilia-associated respiratory (CAR) bacillus, whether Mycoplasma pulmonis can affect expression of CAR bacillus disease, and whether isolates of CAR bacillus differ in virulence for rats. In the first experiment, 24 rats of each strain were inoculated intranasally with 10(7) bacilli of CAR bacillus X1428D/AS, and 24 rats of each strain were inoculated with sterile medium (controls). Eight weeks later, eight inoculated rats and eight control rats of each strain were euthanatized, eight inoculated and eight control rats were given 10(6.5) colony-forming units of M. pulmonis X1428D, and eight inoculated rats and eight control rats were sham inoculated. Four rats of each group were euthanatized 4 or 8 weeks after the second inoculation. Severity of lesions in nasal passages, middle ear, trachea, and lungs was assessed by scoring. Rats of all three strains given CAR bacillus had typical lesions of similar severity; M. pulmonis X1428D was avirulent and did not exacerbate CAR bacillus disease. In the second experiment, groups of eight rats of F344 and SD strains were given 10(5) or 10(7) CAR bacillus X1328E, X1428D/AS, or X2450D and euthanatized 8 or 16 weeks later. Isolates X1428D/AS and X2450D caused similar lesions in rats of both strains and at both doses, but CAR bacillus X1328E was avirulent. Rats of the tested strains are similarly susceptible to CAR bacillus disease, but CAR bacillus isolates differ in virulence.

Demonstration of rat CAR bacillus using a labelled streptavidin biotin (LSAB) method

Immunohistochemical detection of rat CAR bacillus antigen in paraffin-embedded experimentally infected rat lungs, using an immunoperoxidase technique based on the labelled streptavidin biotin (LSAB) method and 3-amino-9-ethylcarbazole (AEC) as substrate is described in this paper. The pattern of immunostaining was confined to the ciliated bronchial epithelium and the specificity of this technique was confirmed. The use of AEC as substrate was evaluated more efficient than diaminobenzidine (DAB). The usefulness of this immunoperoxidase technique for the detection of CAR bacillus in rats and its advantages compared to the indirect immunofluorescence (IF) are discussed.

Morphological evidence of a filamentous cilia-associated respiratory (CAR) bacillus in goats

A filamentous cilia-associated respiratory (CAR) bacillus was discovered in 12 3-4 month-old goats experimentally infected with two different strains of mycoplasmas belonging to the Mycoplasma mycoides type. The CAR bacilli were always arranged parallel to the cilia, and the morphology of these bacilli is very similar to that of other bacilli described previously in other species from various parts of the world.

Detection of cilia-associated respiratory bacillus in experimentally and naturally infected mice and rats by the polymerase chain reaction

Cilia-associated respiratory (CAR) bacillus was detected by means of the reverse transcription (RT)-polymerase chain reaction (PCR), and the results were compared with those of indirect immunofluorescence test (IFAT) for the detection of the organism. In the experimental infections, 15 mice were in contact with mice previously inoculated with CAR bacillus. Three mice each were tested at days 3, 5, 7, 12 and 20 postexposure. On day 3 postexposure, CAR bacillus was detected in oral swab samples from all 3 mice by RT-PCR, but was not detected in any sampling sites from the mice by IFAT. Total numbers of positive samples from nasal, oral and tracheal swabs obtained through the test were 6/15, 14/15 and 8/15, respectively, by RT-PCR, and 2/15, 6/15 and 3/15, respectively by IFAT. For the detection of CAR bacillus in samples from 52 rats, 34 serum antibody negative rats by enzyme-linked immunosorbent assay were also negative by RT-PCR and IFAT except for one sample from the oral cavity, and all serum antibody positive rats were positive for the organism by RT-PCR but it could not be detected in five of them by IFAT. By means of RT-PCR, no differences in the positive rates depending on sampling sites were observed except in one rat. The RT-PCR was found to be a specific, highly sensitive and reliable procedure for detecting CAR bacillus in mice and rats. The oral cavity was the most suitable site for the diagnosis of the early stage of this infection by RT-PCR.

Characterization of cilia-associated respiratory bacillus in rabbits and analysis of the 16S rRNA gene sequence

The cilia-associated respiratory (CAR) bacillus is an unclassified, gram-negative bacterium that has been implicated as an etiologic agent of respiratory tract disease in laboratory rodents. A morphologically and antigenically similar organism has been identified in rabbits and is thought to be a related bacterium, although clinical signs of disease and histologic lesions are absent in infected rabbits. To compare the pathogenicity of rat- and rabbit-origin CAR bacillus isolates in rabbits, neonatal rabbits were experimentally infected with CAR bacillus isolates obtained from an infected rat and rabbit. Rabbits experimentally inoculated with rabbit-origin CAR bacillus had a nasal discharge, seroconverted and developed histologic lesions, whereas rabbits inoculated with rat-origin CAR bacillus seroconverted but did not have evidence of colonization of the respiratory tract. The CAR bacillus isolates were further examined at the genetic level by sequencing 1,261 base pairs of the 16S rRNA gene from six CAR bacillus isolates obtained from infected rabbits. A consensus sequence was obtained and compared with the analogous gene sequence data from rat-origin CAR bacillus isolates. Results indicated that these two organisms are distinctly different, with only 48.8% sequence homology. Comparison of the rabbit-origin 16S rRNA gene sequence with the database Genbank indicated that the organism is most closely related to members of the genus Helicobacter. Bacteria with the highest percentage of similarity with the rabbit-origin CAR bacillus were Helicobacter sp. strain Seymour and H. felis, with 91.1 and 90.8%, respectively. Findings of this study indicate that CAR bacillus isolates from rats and rabbits are host-specific and are different bacteria that belong to distinct genera.

The effect of variations in the expression of pili on the interaction of Neisseria meningitidis with human nasopharyngeal epithelium

Bacterial adherence is essential to colonization of the nasopharynx by Neisseria meningitidis, and pili may facilitate adherence. Scanning electron microscopy and immunogold labeling were used to study the interaction of 2 piliated and 1 nonpiliated variant of N. meningitidis with nasopharyngeal mucosa in an adenoid organ culture system with an air-mucosal interface. Meningococcal infection caused epithelial damage, loss of ciliated epithelium, and ciliary disorganization, which progressed with time and were greater with the piliated strains. Pili increased adherence of meningococci to the mucosa, and there was tropism of piliated strains for nonciliated cells containing microvilli, damaged epithelium, and sites of cell separation. Bacterial adherence was associated with a change in the appearance of the microvilli.

Glycolipid receptors for attachment of Mycoplasma hyopneumoniae to porcine respiratory ciliated cells

Glycolipid receptors for Mycoplasma hyopneumoniae attachment were analyzed by using a thin-layer chromatography (TLC) overlay assay. M. hyopneumoniae bound specifically to sulfatide, globoside, and monosialoganglioside GM3. No binding to sphingomyelin, cerebroside, lactosyl ceramide, ceramide trihexoside, monosialogangliosides GM1 and GM2, disialogangliosides (GD1a, GD1b, and GD3), trisialoganglioside (GT1b), cholesterol, cholesterol sulfate, palmitic acid, tripalmitin, or cholesteryl palmitate was detected. Total lipids extracted from cilia of the swine respiratory epithelium, the natural targets of M. hyopneumoniae infection, were also separated on TLC plates and overlaid with mycoplasmas. M. hyopneumoniae bound specifically to three ciliary glycolipids identified as La, Lb, and Lc. Binding to Lc was stronger than to La and Lb. All three lipids were believed to be sulfated glycolipids, as determined by laminin binding and staining with azure A. Lc was identified as a putative sulfatide because it has a mobility similar to that of authentic sulfatide and comigrated with sulfatide on TLC plates. Laminin bound to La, Lb, and Lc and produced dose-dependent inhibition of adherence of the mycoplasma to the three ciliary receptors. Binding of the mycoplasma to sulfatide, La, Lb, and Lc was partially inhibited by dextran sulfate, heparin, fucoidan, mucin, and chondroitin sulfate B. These substances blocked the adherence of M. hyopneumoniae to cilia and ciliated cells as shown in a previous study (Q. Zhang, T. F. Young, and R. F. Ross, Infect. Immun. 62:1616-1622, 1994). These results indicate that La, Lb, and Lc are the major native receptors for M. hyopneumoniae adherence to ciliated cells.

Characterization of cilia-associated respiratory bacillus isolates from rats and rabbits

Isolates of the cilia-associated respiratory (CAR) bacillus were harvested from the trachea of three naturally infected rats and five naturally infected rabbits and were grown on 3T3 mouse fibroblast cells. Isolates were compared by growth characteristics in mammalian cell culture, by use of protein and DNA analyses, and by experimental infections of BALB/c mice. Examination of CAR bacillus isolates by transmission electron microscopy indicated that organisms from rats and rabbits were similar in appearance and had an acidic mucopolysaccharide layer. In culture, the isolates from rats appeared larger than the rabbit isolates and formed large multiorganism aggregates, whereas isolates obtained from rabbits did not. Protein and antigenic analyses and DNA ribotyping revealed minor differences between isolates but could not be used to distinguish the rat from the rabbit isolates. Mice experimentally inoculated with CAR bacillus of rat origin developed interciliary colonization, seroconverted, and developed microscopic pulmonary lesions. Mice inoculated with isolates of rabbit origin did not display intraciliary colonization, seroconvert, or develop pulmonary disease. The findings of this study indicate that CAR bacillus isolates of rat and rabbit origins may be distinct strains and suggest that, in mice, isolates of rat origin may be more virulent than those of rabbit origin.

Microtiter plate adherence assay and receptor analogs for Mycoplasma hyopneumoniae

A microtiter plate adherence assay for Mycoplasma hyopneumoniae was established by use of purified swine tracheal cilia which contained receptors for the mycoplasmas. M. hyopneumoniae bound specifically to plates coated with solubilized cilia. The binding was dependent on both the concentration of cilia and the number of mycoplasmas. Dextran sulfate, heparin, chondroitin sulfate, laminin, mucin, and fucoidan significantly inhibited the binding of the mycoplasmas. The six inhibitors also disrupted the adherence of the mycoplasmas to intact ciliated cells. Preincubation with either mycoplasmas or cilia indicated that heparin, mucin, fucoidan, and chondroitin sulfate interacted with the adhesive molecules on the surface of the mycoplasmas, while laminin blocked the receptors in cilia. The basis for the inhibition induced by dextran sulfate was unknown. Treatment of cilia with neuraminidase appeared to promote adherence of the mycoplasmas, whereas treatment of cilia with sodium metaperiodate decreased binding. These results indicate that receptors for M. hyopneumoniae in the ciliated epithelium of the respiratory tract of pigs are glycoconjugate in nature.

Effects of Ureaplasma diversum on bovine oviductal explants: quantitative measurement using a calmodulin assay

Calmodulin (CAM) acts as an intracellular regulator of calcium, an important mediator of many cell processes. We used the CAM assay and electron microscopy to investigate the effects of Ureaplasma diversum on bovine oviductal explants obtained aseptically from slaughtered cows. A stock suspension of U. diversum (treated specimens) and sterile broth (controls) was added to replicates of cultured explants and incubated at 38 degrees C in an atmosphere of 5.5% CO2 for 48 hours. Explants were examined for ciliary activity, extracellular CAM loss, and for histological and ultrastructural changes. Explants and their culture media were examined for changes in CAM concentration. All experiments were replicated three times. In addition, U. diversum, medium and broth were assayed for CAM content. The concentrations of CAM in explants and media changed significantly (p < 0.05) in samples which were inoculated with U. diversum when compared to controls. The controls and infected specimens did not differ histologically or ultrastructurally, but U. diversum was seen to be closely associated with infected explant tissue. In view of this close affinity it is assumed the loss of CAM from the oviductal cells was causally related, but this was not proven. The failure to show cell membrane injury on light and electron microscopic examination was probably related to the short duration of the experiment and may only point out the sensitivity of the CAM assay in detecting early cell membrane injury. Compromise in characteristics of the medium to support both, the viability of oviductal cells and U. diversum limited the experimental time to 48 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adherence of Mycoplasma hyopneumoniae to porcine ciliated respiratory tract cells

Adherence of Mycoplasma hyopneumoniae to the mucosa of the distal portion of the respiratory tract of swine is an important initial event in development of mycoplasmal pneumonia. A suitable in vitro model of adherence would be useful for investigation of mycoplasmal and host cell factors involved in this process. We have developed an adherence assay, using suspensions of porcine respiratory tract ciliated epithelial cells and M hyopneumoniae. Tracheal epithelial cells, collected by use of cytologic brushes, were mixed with broth cultures of M hyopneumoniae and the mixtures were incubated, diluted, vortexed, and sedimented. Pellets were spread on glass slides, stained with a fluorescent antibody against M hyopneumoniae, and evaluated by fluorescent microscopy. Fluorescence was observed principally among cilia on the ciliated tufts of epithelial cells. Only a few organisms were observed adhering on the nonciliated parts of ciliated cells or on other cell types. When mycoplasmas were preincubated with low dilutions of serum from swine convalescing from M hyopneumoniae disease, attachment was partially inhibited (P < 0.05). Significant inhibition of attachment was not observed when organisms were preincubated with higher dilutions of convalescent serum, with purified IgG from hyperimmune serum against M hyopneumoniae, or with low dilutions of lung lavage fluids (from convalescent swine) that contained specific IgA antibodies against M hyopneumoniae. Preincubation of the organisms with periodate and trypsin abolished attachment and formaldehyde decreased it (P < 0.05), whereas a variety of carbohydrates had no effect on attachment. Preincubation with dextran sulfate, ammonium sulfate, magnesium sulfate, and methionine reduced attachment (P < 0.05). Treatment of cell-Mycoplasma mixtures with the hydrophobic bond-breaking agent tetramethylurea, or incubation in absence of salt, or at low temperature also reduced attachment (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Sites of predilection in recurrent respiratory papillomatosis

Florid and widespread respiratory papillomatosis is a devastating disorder in a subset of patients with recurrent respiratory papillomatosis, and it poses a major dilemma for the patient and the surgeon. Contrary to common belief, the distribution of papilloma lesions is not random, but follows a predictable pattern, with lesions occurring at anatomic sites in which ciliated and squamous epithelia are juxtaposed. The predominant sites of disease in recurrent respiratory papillomatosis are the limen vestibuli, the nasopharyngeal surface of the soft palate, the midzone of the laryngeal surface of the epiglottis, the upper and lower margins of the ventricle, the undersurface of the vocal folds, the carina, and bronchial spurs. These sites have the common histologic feature of a squamociliary junction. Papillomata also occur at the tracheostomy tract and at the midthoracic trachea in patients with tracheostomies. At the latter sites, abrasion injury to ciliated epithelium heals with metaplastic squamous epithelium and creates an iatrogenic squamociliary junction. The apparent preferential localization of papilloma at squamociliary junctions has at least 2 implications: first, that detection of occult asymptomatic papillomata is enhanced by careful examination of squamociliary junctions, and, second, that iatrogenic papilloma "implantation" is preventable by avoiding injury to nondiseased squamous and ciliated epithelia.

Effect of influenza A virus on ciliary activity and dye transport function in the chinchilla eustachian tube

Previous studies have shown that influenza A virus inoculated via a transbullar approach can cause severe disorders of the chinchilla eustachian tube. In this study, we inoculated chinchillas both intranasally and transbullarly with influenza A virus (A/Alaska/6/77) to assess the effect of this virus on both the ciliary activity of eustachian tube epithelium and eustachian tube transport function. Data indicated that while the nature of the major lesions was indistinguishable, the differing routes of inoculation did influence the time course and initial location of virus-induced histopathology. Analysis of ciliary beat frequency and dye transport function indicated a maximal decrease approximately 7 to 14 days postinoculation, with return to normal function by 28 days postinoculation. Light and transmission electron microscopic observations of the evolution of histopathology and return to normal histology correlated well with functional assessment data.

Detection of Mycoplasma hyorhinis in porcine eustachitis

Pathologic study of the ear was performed on 179 young swine, ranging in age from 1 day to 18.6 weeks. Histologically, eustachitis was the most common and its inflammatory reaction appeared to precede otitis. Immunohistochemically, Mycoplasma hyorhinis (Mhr) antigens were detected on the luminal surface of the auditory epithelia in 19 of 179 cases (10.6%). All the cases, positive for Mhr antigens, were associated with an acute eustachitis. Ultrastructural examination of two piglets confirmed these immunohistochemical data. The present results indicate that Mhr may be a primary cause of acute eustachitis in young swine.

In vitro study of the bronchial mucosa during Pseudomonas aeruginosa infection

The route of bacterial infection of the lower respiratory tract is generally one of descent subsequent to colonisation of the oral and oropharyngeal mucosa. The interaction between Pseudomonas aeruginosa (wild type) and the bronchial epithelium was studied in bronchial mucosal probes cultured in tissue culture medium. It was possible to demonstrate that, even after loss of the mucus layer, adherence between the bacteria and the bronchial epithelium does not take place if ciliary function remains intact. Only after mechanical destruction of the bronchial epithelium, in proximity to squamous metaplasia or after loss or malfunction of the cilia of the bronchial epithelial cells was adhesion between bacteria and bronchial epithelial cells or basement membrane demonstrated by electron microscopy. After loss of the cilia following adenovirus-infection, adhesion between P. aeruginosa and the bronchial epithelial cells was visible. These results indicate that ciliary function must be of crucial significance in bacterial epithelial colonisation.

Two types of bacteria adherent to bovine respiratory tract ciliated epithelium

Two hundred sixty tracheas were obtained from a Philadelphia abattoir under permit from the Department of Agriculture; the tracheas were excised from predominantly Holstein calves of both sexes that weighed approximately 250 kg. Tracheas were transported in normal saline to the laboratory at Thomas Jefferson University, Philadelphia, Pennsylvania. Evidence of bacteria adherent to the tracheal epithelium was found in specimens from 20/24 of these tracheas. The epithelium from each of five tracheas was placed in glutaraldehyde fixative for transmission electron microscopic examination. Epithelium from each of 12 other tracheas was placed in formaldehyde fixative for light microscopic examination. Microscopically, 13 of these 17 bovine tracheal epithelia were observed to contain bacteria located longitudinally parallel to and between cilia and microvilli of ciliated cells. Preparations of ciliary axonemes isolated from the epithelium of seven additional bovine tracheas also contained these bacteria in sections viewed by a transmission electron microscope. These bacteria had two different ultrastructural morphologies: filamentous with a trilaminar-structured cell wall and short with a thick, homogeneously stained cell wall beneath a regularly arrayed surface layer. The short bacillus had surface carbohydrates, including mannose, galactose, and N-acetylgalactosamine, identified by lectin binding. The filamentous bacillus was apparently externally deficient in these carbohydrates. Immunogold staining revealed that the filamentous bacillus was antigenically related to cilia-associated respiratory (CAR) bacillus, which has been identified in rabbit and rodent species. Significantly decreased numbers of cilia were obtained from tracheal epithelium heavily colonized by the filamentous bacilli, suggesting a pathologic change in ciliated cells.

Cytological and histological changes in the middle ear after inoculation of influenza A virus

Experimental otitis media induced in the chinchilla by inoculation of influenza A virus into the middle ear resulted in capillary engorgement, subepithelial hemorrhage, tissue edema and acute inflammatory cell infiltration. Quantitative morphometric measurements were made for 28 days. Ciliated cells appeared to be the primary target of this strain of influenza virus and demonstrated the greatest degree of damage. Three weeks were required to restore the ciliated epithelium in the tubotympanum to normal levels.

Cilia-associated respiratory bacillus in wild rats in central Iowa

Twenty-eight wild rats were live-trapped in central Iowa (USA) to estimate the prevalence of the cilia-associated respiratory (CAR) bacillus. Both light and electron microscopy were used to look for the Gram-negative, filamentous bacterium among cilia in tracheal and lung tissue sections. The organism was observed in the trachea of 20 rats with chronic respiratory disease and in the trachea of three of eight normal rats. Therefore, the organism appears to be common among wild rats in central Iowa.

Interaction of Haemophilus influenzae with mucus, cilia, and respiratory epithelium

One nontypeable laboratory strain and five nontypeable clinical isolates of Haemophilus influenzae from sputum were investigated. Bacteria replicated from 10(4) to 10(8) cfu/ml over 24 h in an organ culture of human respiratory mucosa with only the intact mucosal surface exposed. By transmission electron microscopy, bacteria were not seen in association with normal respiratory epithelium, even after incubation for 24 h. H. influenzae infection caused patchy and occasionally confluent damage to epithelium, and the bacteria associated only with structurally damaged cells. Scanning electron microscopy revealed increased mucus, and slowed ciliary beat frequency was measured by photometry. Fimbriation of H. influenzae increased buccal cell adherence but did not facilitate association with normal or damaged respiratory epithelium or increase epithelial damage, indicating that adhesins other than fimbriae are present. Interactions with mucus, cilia, and epithelium are likely to be important in the pathogenesis of H. influenzae respiratory infections.